/* GIO - GLib Input, Output and Streaming Library * * Copyright (C) 2009 Red Hat, Inc. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General * Public License along with this library; if not, write to the * Free Software Foundation, Inc., 59 Temple Place, Suite 330, * Boston, MA 02111-1307, USA. * * Author: Alexander Larsson */ #include "config.h" #include "gasyncinitable.h" #include "gasyncresult.h" #include "gsimpleasyncresult.h" #include "glibintl.h" /** * SECTION:gasyncinitable * @short_description: Asynchronously failable object initialization interface * @include: gio/gio.h * @see_also: #GInitable * * This is the asynchronous version of #GInitable; it behaves the same * in all ways except that initialization is asynchronous. For more details * see the descriptions on #GInitable. * * A class may implement both the #GInitable and #GAsyncInitable interfaces. * * Users of objects implementing this are not intended to use the interface * method directly; instead it will be used automatically in various ways. * For C applications you generally just call g_async_initable_new_async() * directly, or indirectly via a foo_thing_new_async() wrapper. This will call * g_async_initable_init_async() under the cover, calling back with %NULL and * a set %GError on failure. */ static void g_async_initable_real_init_async (GAsyncInitable *initable, int io_priority, GCancellable *cancellable, GAsyncReadyCallback callback, gpointer user_data); static gboolean g_async_initable_real_init_finish (GAsyncInitable *initable, GAsyncResult *res, GError **error); typedef GAsyncInitableIface GAsyncInitableInterface; G_DEFINE_INTERFACE (GAsyncInitable, g_async_initable, G_TYPE_OBJECT) static void g_async_initable_default_init (GAsyncInitableInterface *iface) { iface->init_async = g_async_initable_real_init_async; iface->init_finish = g_async_initable_real_init_finish; } /** * g_async_initable_init_async: * @initable: a #GAsyncInitable. * @io_priority: the I/O priority * of the operation. * @cancellable: optional #GCancellable object, %NULL to ignore. * @callback: a #GAsyncReadyCallback to call when the request is satisfied * @user_data: the data to pass to callback function * * Starts asynchronous initialization of the object implementing the * interface. This must be done before any real use of the object after * initial construction. If the object also implements #GInitable you can * optionally call g_initable_init() instead. * * When the initialization is finished, @callback will be called. You can * then call g_async_initable_init_finish() to get the result of the * initialization. * * Implementations may also support cancellation. If @cancellable is not * %NULL, then initialization can be cancelled by triggering the cancellable * object from another thread. If the operation was cancelled, the error * %G_IO_ERROR_CANCELLED will be returned. If @cancellable is not %NULL, and * the object doesn't support cancellable initialization, the error * %G_IO_ERROR_NOT_SUPPORTED will be returned. * * If this function is not called, or returns with an error, then all * operations on the object should fail, generally returning the * error %G_IO_ERROR_NOT_INITIALIZED. * * Implementations of this method must be idempotent: i.e. multiple calls * to this function with the same argument should return the same results. * Only the first call initializes the object; further calls return the result * of the first call. This is so that it's safe to implement the singleton * pattern in the GObject constructor function. * * For classes that also support the #GInitable interface, the default * implementation of this method will run the g_initable_init() function * in a thread, so if you want to support asynchronous initialization via * threads, just implement the #GAsyncInitable interface without overriding * any interface methods. * * Since: 2.22 */ void g_async_initable_init_async (GAsyncInitable *initable, int io_priority, GCancellable *cancellable, GAsyncReadyCallback callback, gpointer user_data) { GAsyncInitableIface *iface; g_return_if_fail (G_IS_ASYNC_INITABLE (initable)); iface = G_ASYNC_INITABLE_GET_IFACE (initable); (* iface->init_async) (initable, io_priority, cancellable, callback, user_data); } /** * g_async_initable_init_finish: * @initable: a #GAsyncInitable. * @res: a #GAsyncResult. * @error: a #GError location to store the error occuring, or %NULL to * ignore. * * Finishes asynchronous initialization and returns the result. * See g_async_initable_init_async(). * * Returns: %TRUE if successful. If an error has occurred, this function * will return %FALSE and set @error appropriately if present. * * Since: 2.22 */ gboolean g_async_initable_init_finish (GAsyncInitable *initable, GAsyncResult *res, GError **error) { GAsyncInitableIface *iface; g_return_val_if_fail (G_IS_ASYNC_INITABLE (initable), FALSE); g_return_val_if_fail (G_IS_ASYNC_RESULT (res), FALSE); if (G_IS_SIMPLE_ASYNC_RESULT (res)) { GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (res); if (g_simple_async_result_propagate_error (simple, error)) return FALSE; } iface = G_ASYNC_INITABLE_GET_IFACE (initable); return (* iface->init_finish) (initable, res, error); } static void async_init_thread (GSimpleAsyncResult *res, GObject *object, GCancellable *cancellable) { GError *error = NULL; if (!g_initable_init (G_INITABLE (object), cancellable, &error)) { g_simple_async_result_set_from_error (res, error); g_error_free (error); } } static void g_async_initable_real_init_async (GAsyncInitable *initable, int io_priority, GCancellable *cancellable, GAsyncReadyCallback callback, gpointer user_data) { GSimpleAsyncResult *res; g_return_if_fail (G_IS_INITABLE (initable)); res = g_simple_async_result_new (G_OBJECT (initable), callback, user_data, g_async_initable_real_init_async); g_simple_async_result_run_in_thread (res, async_init_thread, io_priority, cancellable); g_object_unref (res); } static gboolean g_async_initable_real_init_finish (GAsyncInitable *initable, GAsyncResult *res, GError **error) { return TRUE; /* Errors handled by base impl */ } /** * g_async_initable_new_async: * @object_type: a #GType supporting #GAsyncInitable. * @io_priority: the I/O priority * of the operation. * @cancellable: optional #GCancellable object, %NULL to ignore. * @callback: a #GAsyncReadyCallback to call when the initialization is * finished * @user_data: the data to pass to callback function * @first_property_name: the name of the first property, or %NULL if no * properties * @...: the value of the first property, followed by other property * value pairs, and ended by %NULL. * * Helper function for constructing #GAsyncInitiable object. This is * similar to g_object_new() but also initializes the object asynchronously. * * When the initialization is finished, @callback will be called. You can * then call g_async_initable_new_finish() to get the new object and check * for any errors. * * Since: 2.22 */ void g_async_initable_new_async (GType object_type, int io_priority, GCancellable *cancellable, GAsyncReadyCallback callback, gpointer user_data, const gchar *first_property_name, ...) { va_list var_args; va_start (var_args, first_property_name); g_async_initable_new_valist_async (object_type, first_property_name, var_args, io_priority, cancellable, callback, user_data); va_end (var_args); } /** * g_async_initable_newv_async: * @object_type: a #GType supporting #GAsyncInitable. * @n_parameters: the number of parameters in @parameters * @parameters: the parameters to use to construct the object * @io_priority: the I/O priority * of the operation. * @cancellable: optional #GCancellable object, %NULL to ignore. * @callback: a #GAsyncReadyCallback to call when the initialization is * finished * @user_data: the data to pass to callback function * * Helper function for constructing #GAsyncInitiable object. This is * similar to g_object_newv() but also initializes the object asynchronously. * * When the initialization is finished, @callback will be called. You can * then call g_async_initable_new_finish() to get the new object and check * for any errors. * * Since: 2.22 */ void g_async_initable_newv_async (GType object_type, guint n_parameters, GParameter *parameters, int io_priority, GCancellable *cancellable, GAsyncReadyCallback callback, gpointer user_data) { GObject *obj; g_return_if_fail (G_TYPE_IS_ASYNC_INITABLE (object_type)); obj = g_object_newv (object_type, n_parameters, parameters); g_async_initable_init_async (G_ASYNC_INITABLE (obj), io_priority, cancellable, callback, user_data); } /** * g_async_initable_new_valist_async: * @object_type: a #GType supporting #GAsyncInitable. * @first_property_name: the name of the first property, followed by * the value, and other property value pairs, and ended by %NULL. * @var_args: The var args list generated from @first_property_name. * @io_priority: the I/O priority * of the operation. * @cancellable: optional #GCancellable object, %NULL to ignore. * @callback: a #GAsyncReadyCallback to call when the initialization is * finished * @user_data: the data to pass to callback function * * Helper function for constructing #GAsyncInitiable object. This is * similar to g_object_new_valist() but also initializes the object * asynchronously. * * When the initialization is finished, @callback will be called. You can * then call g_async_initable_new_finish() to get the new object and check * for any errors. * * Since: 2.22 */ void g_async_initable_new_valist_async (GType object_type, const gchar *first_property_name, va_list var_args, int io_priority, GCancellable *cancellable, GAsyncReadyCallback callback, gpointer user_data) { GObject *obj; g_return_if_fail (G_TYPE_IS_ASYNC_INITABLE (object_type)); obj = g_object_new_valist (object_type, first_property_name, var_args); g_async_initable_init_async (G_ASYNC_INITABLE (obj), io_priority, cancellable, callback, user_data); g_object_unref (obj); /* Passed ownership to async call */ } /** * g_async_initable_new_finish: * @initable: the #GAsyncInitable from the callback * @res: the #GAsyncResult.from the callback * @error: a #GError location to store the error occuring, or %NULL to * ignore. * * Finishes the async construction for the various g_async_initable_new calls, * returning the created object or %NULL on error. * * Returns: a newly created #GObject, or %NULL on error. Free with * g_object_unref(). * * Since: 2.22 */ GObject * g_async_initable_new_finish (GAsyncInitable *initable, GAsyncResult *res, GError **error) { if (g_async_initable_init_finish (initable, res, error)) return g_object_ref (initable); else return NULL; }